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Quad-frequency oscillation from 100 GHz to 200 GHz was demonstrated using ITER gyrotron at QST. Those RF beam passed through the center of the gyrotron window and good couples to transmission line were obtained for each oscillation. The mega-watt-class power was obtained for all frequencies. Validation of gyrotron for a demo reactor is numerically started on the basis of our multi-frequency gyrotron.
Long pulse operation of a dual frequency gyrotron for JT-60SA, which can oscillate both 110 GHz and 138 GHz waves, was started. Oscillations at ∼ 0.4 MW for 2 s (both frequencies) and 0.7 MW for 1 s (110 GHz) were obtained, so far. Temperature increase in the cavity, the output window and some components, which absorb stray radiation in the gyrotron, were measured and cavity loss power and the dielectric...
For direct measurement on hyperfine structure of positronium, high power sub-THz radiation sources, Gyrotrons FU CW V and FU CW VIII have been developed. FU CW V is a frequency fixed gyrotron operating at 203.3 GHz for the proof-of-principle experiment and FU CW VIII a frequency continuously tunable gyrotron to measure directly the energy difference between orth- and para states of positronium.
Microwave heating is one of the key technology in medicine such as sterilization, synthesis of pharmacy and treatment. In application, it is necessary to obtain temperature dependent complex permittivity of material. For accurate measurement, one way is to apply a cylindrical cavity resonator. To apply microwave heating using the cavity resonator, it becomes possible to measure the temperature dependent...
Gyrotron FU CW V operating at the fundamental cyclotron resonance is used for measurement of hyperfine structure on positronium. The gyrotron delivers high power radiation with the frequency of 203.2 GHz and output power of 0.7 kW under CW operation mode. This radiation can be used for direct measurement of energy level transition of positronium, because expected energy level difference is near 203...
Recent progresses in gyrotron development and related technologies are presented. The gyrotron demonstrated ITER relevant parameters at 170 GHz (1 MW, 800 s, 55 %), and proved a reliability with long operation period. Recently, one hour operation was obtained at 0.8 MW with the efficiency of 57 %, and total output energy of 190 GJ was recorded with 2 years operation. On the other hand, a power increase...
Accurate measurement of difference between energy levels of positronium is a current important subject in the experimental physics of elementary particles. The frequency corresponding to the energy difference is about 203.39 GHz. At least, 100 watt CW power is requested for the direct measurement. We are now designing such a gyrotron FU CW V consisting of an 8 T superconducting magnet and a demountable...
Narrow-band thermal radiation is presented using a periodic array of microcavities on tungsten surfaces. Thermally excited modes inside the microcavities are found to resonantly enhance thermal radiation at specific wavelengths
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